The Experts below are selected from a list of 4050 Experts worldwide ranked by ideXlab platform
Hiroyuki Yano - One of the best experts on this subject based on the ideXlab platform.
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Compressive deformation of phenol formaldehyde (PF) resin-Impregnated Wood related to the molecular weight of resin
Wood Science and Technology, 2010Co-Authors: Iftekhar Shams, Hiroyuki YanoAbstract:The effects of molecular weight of PF resin on the deformation behaviour of NaClO2 treated resin-Impregnated Wood during compression were investigated. Blocks of Japanese cedar were subjected to 2% NaClO2 aqueous solution. This was repeated up to four times resulting in a weight loss of 28%. Treated and untreated samples were Impregnated with PF resin having different molecular weight. With increasing molecular weight, weight gain and volume gain decreased for untreated PF resin-Impregnated Wood, while NaClO2 treated Wood Impregnated with high molecular weight PF resin showed almost double the weight gain compared to untreated condition. NaClO2 treatment has shown considerable potential for high compression of PF resin-Impregnated Wood at lower pressing pressure regardless of the molecular weight of the resin. Low to high molecular weight resin was shown to penetrate into NaClO2 treated Wood as estimated by weight gain contributing to the plasticization of cell wall considerably and thus resulting in cell wall collapse at low pressing pressure. The density of NaClO2 treated Wood Impregnated with high molecular weight resin attained a value of over 0.8 g/cm3 which is close to the density of untreated Wood Impregnated with low molecular weight resin. Such compressed Wood exhibited high dimensional stability after boiling for 3 h. Thus, the penetration of resin into Wood contributes to highly compressed dimensional stable resin-Impregnated Wood at low pressing pressure.
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A new method for obtaining high strength phenol formaldehyde resin-Impregnated Wood composites at low pressing pressure.
Journal of Tropical Forest Science, 2009Co-Authors: Iftekhar Shams, Hiroyuki YanoAbstract:SHAMS MI & YANO H. 2009. A new method for obtaining high strength phenol formaldehyde resinImpregnated Wood composites at low pressing pressure. To obtain high strength phenol formaldehyde (PF) resin-Impregnated compressed Wood at low pressure, we investigated the effects of sodium chlorite treatment followed by sodium hydroxide treatment prior to low molecular weight PF resin impregnation. Sawn veneers of Japanese cedar (Cryptomeria japonica) were first treated with 2% aqueous solution of NaClO2 followed by 0.5% aqueous solution of NaOH. A total weight loss of 12% was obtained by the combination of these two treatments. It was found that the treatments showed potential for the marked deformation of PF resinImpregnated Wood at low pressure. The result suggests that depolymerization or partial removal of lignin can be effective for the removal of hemicellulose, which softens the cell wall swollen by PF resin and makes it possible to compress Wood remarkably at low pressing pressure. Pressure holding during compression caused creep deformation of resin-Impregnated Wood and resulted in density, Young’s modulus (MOE) and bending strength (MOR) of 1.16 g cm-3, 29 GPa and 307 MPa respectively at a pressing pressure of 1 MPa. This technique imparts high strength and attractive surface to plyWood and other Wood composite materials with conventional hot press equipment.
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Compressive deformation of Wood Impregnated with low molecular weight phenol formaldehyde (PF) resin V: effects of steam pretreatment
Journal of Wood Science, 2006Co-Authors: Md. Iftekhar Shams, Toshiro Morooka, Hiroyuki YanoAbstract:This study evaluated the potential of steam pre-treatment for making highly compressed phenol-formaldehyde (PF) resin-Impregnated Wood at a low pressing pressure. Sawn veneers of Japanese cedar ( Cryptomeria japonica ) were first subjected to saturated steam at different steaming temperatures (140°-200°C), followed by impregnation with a 20% low molecular weight PF resin aqueous solution resulting in a weight gain of around 50%-55%. Four oven-dried treated veneers were laminated and compressed up to a pressing pressure of 1 MPa at a pressing temperature of 150°C and pressing speed of 5 mm/min, and the pressure was held for 30 min. Steam treatment, causing partial hydrolysis of hemicellulose, accelerated the compressibility of Japanese cedar in the PF resin-swollen condition. As a consequence, a discernible increment in density was achieved at a pressing pressure of 1 MPa due to steam pretreatment between 140° and 200°C for 10 min. It was also found that even a short steaming time such as 2 min at 160°C is sufficient for obtaining appreciable compression of PF resin-Impregnated Wood. The density, Young’s modulus, and bending strength of steam-treated (200°C for 10 min) PF resin-Impregnated Wood composite reached 1.09 g/cm^3, 20 GPa, and 207MPa, respectively. In contrast, the values of untreated PF resin-Impregnated Wood composite were 0.87 g/cm^3, 13 GPa, and 170MPa, respectively.
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Compressive deformation of Wood Impregnated with low molecular weight phenol formaldehyde (PF) resin IV: Species dependency
Journal of Wood Science, 2006Co-Authors: Iftekhar Shams, Noriko Kagemori, Hiroyuki YanoAbstract:Flat-sawn specimens of eight Wood species, albizia (Paraserianthes falkata, 0.23 g/cm3), Japanese cedar (Cryptomeria japonica, 0.31 g/cm3), red lauan (Shorea sp., 0.36 g/cm3), European spruce (Picea abies, 0.44 g/cm3), Douglas fir (Pseudotsuga douglasii, 0.50 g/cm3), elm (Ulmus sp., 0.51 g/cm3), Japanese beech (Fagus crenata, 0.64 g/cm3), and Japanese birch (Betula maximowicziana, 0.71 g/cm3), were Impregnated with low molecular weight phenol-formaldehyde (PF) resin and their compressive deformations were compared. The volume gain (VG) and weight gain due to 20% resin solution impregnation were different among species. Furthermore, the specific volume gain (VG/specific gravity), indicating the degree of swelling of the cell wall, also varied from 17.7% for European spruce to 26.4% for elm. Oven-dried specimens of each species were compressed using hot plates fixed to an Instron testing machine. The deformation behavior of resin-Impregnated Wood up to 10MPa was significantly different among the species. Stress development during cell wall collapse for low density Wood was minimal. As a consequence, a significant increment of density occurred up to 2MPa for low density Wood such as albizia and Japanese cedar. When PF resin-Impregnated Wood was compressed up to 2MPa and the pressure was kept constant for 30min, the density of Japanese cedar reached 1.18g/cm3, about 30% higher than the density of compressed Japanese birch, which possesses an original density that is 2.5 times higher than that of Japanese cedar. The mechanical properties of resin-Impregnated Wood, especially low density Wood, increased with density. Hence, it is manifested that low density Wood species have an advantage as raw materials for obtaining high-strength Wood at low pressing pressure.
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Compressive deformation of Wood Impregnated with low molecular weight phenol formaldehyde (PF) resin III : effects of sodium chlorite treatment
Journal of Wood Science, 2005Co-Authors: Iftekhar Shams, Hiroyuki Yano, Keijirou EndouAbstract:To obtain high-strength phenol–formaldehyde (PF) resin-Impregnated compressed Wood at low pressing pressure, we investigated the effects of sodium chlorite (NaClO2) treatment on Wood prior to low molecular weight PF resin impregnation. Sawn veneers of Japanese cedar (Cryptomeria japonica) were treated with 2% aqueous NaClO2 solution at 45°C for 12 h to remove lignin, and the process was repeated up to four times, resulting in weight loss of 21%. NaClO2 treatment has shown considerable potential for high compression of PF resin-Impregnated Wood at low pressing pressure, especially after adding moisture to a content of 10%–11%. This deformation is further enhanced during pressure holding by creep deformation. The density, Young’s modulus, and bending strength of PF resin-Impregnated veneer laminated composites that were treated with NaClO2 four times and compressed at 1 MPa, reached 1.15 g/cm3, 27 GPa, and 280 MPa, respectively. The values in untreated PF resin-Impregnated Wood reached 0.8 g/cm3, 16 GPa, and 165 MPa, respectively.
Iftekhar Shams - One of the best experts on this subject based on the ideXlab platform.
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Compressive deformation of phenol formaldehyde (PF) resin-Impregnated Wood related to the molecular weight of resin
Wood Science and Technology, 2010Co-Authors: Iftekhar Shams, Hiroyuki YanoAbstract:The effects of molecular weight of PF resin on the deformation behaviour of NaClO2 treated resin-Impregnated Wood during compression were investigated. Blocks of Japanese cedar were subjected to 2% NaClO2 aqueous solution. This was repeated up to four times resulting in a weight loss of 28%. Treated and untreated samples were Impregnated with PF resin having different molecular weight. With increasing molecular weight, weight gain and volume gain decreased for untreated PF resin-Impregnated Wood, while NaClO2 treated Wood Impregnated with high molecular weight PF resin showed almost double the weight gain compared to untreated condition. NaClO2 treatment has shown considerable potential for high compression of PF resin-Impregnated Wood at lower pressing pressure regardless of the molecular weight of the resin. Low to high molecular weight resin was shown to penetrate into NaClO2 treated Wood as estimated by weight gain contributing to the plasticization of cell wall considerably and thus resulting in cell wall collapse at low pressing pressure. The density of NaClO2 treated Wood Impregnated with high molecular weight resin attained a value of over 0.8 g/cm3 which is close to the density of untreated Wood Impregnated with low molecular weight resin. Such compressed Wood exhibited high dimensional stability after boiling for 3 h. Thus, the penetration of resin into Wood contributes to highly compressed dimensional stable resin-Impregnated Wood at low pressing pressure.
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A new method for obtaining high strength phenol formaldehyde resin-Impregnated Wood composites at low pressing pressure.
Journal of Tropical Forest Science, 2009Co-Authors: Iftekhar Shams, Hiroyuki YanoAbstract:SHAMS MI & YANO H. 2009. A new method for obtaining high strength phenol formaldehyde resinImpregnated Wood composites at low pressing pressure. To obtain high strength phenol formaldehyde (PF) resin-Impregnated compressed Wood at low pressure, we investigated the effects of sodium chlorite treatment followed by sodium hydroxide treatment prior to low molecular weight PF resin impregnation. Sawn veneers of Japanese cedar (Cryptomeria japonica) were first treated with 2% aqueous solution of NaClO2 followed by 0.5% aqueous solution of NaOH. A total weight loss of 12% was obtained by the combination of these two treatments. It was found that the treatments showed potential for the marked deformation of PF resinImpregnated Wood at low pressure. The result suggests that depolymerization or partial removal of lignin can be effective for the removal of hemicellulose, which softens the cell wall swollen by PF resin and makes it possible to compress Wood remarkably at low pressing pressure. Pressure holding during compression caused creep deformation of resin-Impregnated Wood and resulted in density, Young’s modulus (MOE) and bending strength (MOR) of 1.16 g cm-3, 29 GPa and 307 MPa respectively at a pressing pressure of 1 MPa. This technique imparts high strength and attractive surface to plyWood and other Wood composite materials with conventional hot press equipment.
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Compressive deformation of Wood Impregnated with low molecular weight phenol formaldehyde (PF) resin IV: Species dependency
Journal of Wood Science, 2006Co-Authors: Iftekhar Shams, Noriko Kagemori, Hiroyuki YanoAbstract:Flat-sawn specimens of eight Wood species, albizia (Paraserianthes falkata, 0.23 g/cm3), Japanese cedar (Cryptomeria japonica, 0.31 g/cm3), red lauan (Shorea sp., 0.36 g/cm3), European spruce (Picea abies, 0.44 g/cm3), Douglas fir (Pseudotsuga douglasii, 0.50 g/cm3), elm (Ulmus sp., 0.51 g/cm3), Japanese beech (Fagus crenata, 0.64 g/cm3), and Japanese birch (Betula maximowicziana, 0.71 g/cm3), were Impregnated with low molecular weight phenol-formaldehyde (PF) resin and their compressive deformations were compared. The volume gain (VG) and weight gain due to 20% resin solution impregnation were different among species. Furthermore, the specific volume gain (VG/specific gravity), indicating the degree of swelling of the cell wall, also varied from 17.7% for European spruce to 26.4% for elm. Oven-dried specimens of each species were compressed using hot plates fixed to an Instron testing machine. The deformation behavior of resin-Impregnated Wood up to 10MPa was significantly different among the species. Stress development during cell wall collapse for low density Wood was minimal. As a consequence, a significant increment of density occurred up to 2MPa for low density Wood such as albizia and Japanese cedar. When PF resin-Impregnated Wood was compressed up to 2MPa and the pressure was kept constant for 30min, the density of Japanese cedar reached 1.18g/cm3, about 30% higher than the density of compressed Japanese birch, which possesses an original density that is 2.5 times higher than that of Japanese cedar. The mechanical properties of resin-Impregnated Wood, especially low density Wood, increased with density. Hence, it is manifested that low density Wood species have an advantage as raw materials for obtaining high-strength Wood at low pressing pressure.
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Compressive deformation of Wood Impregnated with low molecular weight phenol formaldehyde (PF) resin III : effects of sodium chlorite treatment
Journal of Wood Science, 2005Co-Authors: Iftekhar Shams, Hiroyuki Yano, Keijirou EndouAbstract:To obtain high-strength phenol–formaldehyde (PF) resin-Impregnated compressed Wood at low pressing pressure, we investigated the effects of sodium chlorite (NaClO2) treatment on Wood prior to low molecular weight PF resin impregnation. Sawn veneers of Japanese cedar (Cryptomeria japonica) were treated with 2% aqueous NaClO2 solution at 45°C for 12 h to remove lignin, and the process was repeated up to four times, resulting in weight loss of 21%. NaClO2 treatment has shown considerable potential for high compression of PF resin-Impregnated Wood at low pressing pressure, especially after adding moisture to a content of 10%–11%. This deformation is further enhanced during pressure holding by creep deformation. The density, Young’s modulus, and bending strength of PF resin-Impregnated veneer laminated composites that were treated with NaClO2 four times and compressed at 1 MPa, reached 1.15 g/cm3, 27 GPa, and 280 MPa, respectively. The values in untreated PF resin-Impregnated Wood reached 0.8 g/cm3, 16 GPa, and 165 MPa, respectively.
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compressive deformation of Wood Impregnated with low molecular weight phenol formaldehyde pf resin i effects of pressing pressure and pressure holding
Journal of Wood Science, 2004Co-Authors: Iftekhar Shams, Hiroyuki Yano, Keijirou EndouAbstract:The deformation behavior of low molecular weight phenol formaldehyde (PF) resin-Impregnated Wood under compression in the radial direction was investigated for obtaining high-strength Wood at low pressing pressures. Flat-sawn grain Japanese cedar (Cryptomeria japonica) blocks with a density of 0.34 g/cm3 were treated with aqueous solution of 20% low molecular weight PF resin resulting in weight gain of 60.8%. Oven-dried specimens were compressed using hot plates fixed to a testing machine. The temperature was 150°C and the pressing speed was 5 mm/min. The impregnation of PF resin caused significant softening of the cell walls resulting in collapse at low pressures. The cell wall collapse was strain-dependent and occurred at a strain of 0.05–0.06 mm/mm regardless of whether the Wood was treated with PF resin. Thus, pressure holding causing creep deformation of the cell walls was also effective in initiating cell wall collapse at low pressure. Utilizing a combination of low molecular weight PF resin impregnation and pressure holding at 2 MPa resulted in a density increase of PF resin-treated Wood from 0.45 to 1.1 g/cm3. At the same time, the Young’s modulus and bending strength increased from 10 GPa to 22 GPa and 80 MPa to 250 MPa, respectively. It can be concluded that effective utilization of the collapse region of the cell wall is a desirable method for obtaining high-strength PF resin-Impregnated Wood at low pressing pressures.
Miha Humar - One of the best experts on this subject based on the ideXlab platform.
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Thermal modification of wax-Impregnated Wood to enhance its physical, mechanical, and biological properties
Holzforschung, 2016Co-Authors: Miha Humar, Davor Kržišnik, Boštjan Lesar, Nejc Thaler, Aleš Ugovšek, Klemen Zupančič, Mojca ŽlahtičAbstract:Abstract Thermal modification is the most important commercial modification procedure. Thermally modified (TM) Wood has improved durability, but its performance does not meet expectations predominately under moist conditions. To reduce water uptake of TM Wood, Norway spruce specimens were treated with suspensions of a natural wax by dipping impregnation (DipI) or by vacuum-pressure impregnation (VPI). Wax-treated specimens were subsequently TM at 185, 200, 215, and 230°C. Control specimens were heated up to 100°C only. Contact angle (CA), short-term and long-term water uptake, bending strength, and performance against Wood decay fungi of the resulting material were determined. The results show that a combination of wax treatment and thermal modification have a synergistic effect that considerably improves hydrophobicity, reduces liquid water uptake, slows down water vapor uptake, and improves the resistance against fungal decay of the treated material.
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Leaching of boron from Wood Impregnated with preservative solutions based on boric acid and liquefied Wood
European Journal of Wood and Wood Products, 2012Co-Authors: Boštjan Lesar, Polonca Kralj, Marko Petrič, Franc Budija, Miha HumarAbstract:Reducing boron leaching from Impregnated Wood has been one of the most challenging tasks for at least 50 years. In order to slow down the leaching of boron, aqueous solutions of boric acid were combined with liquefied spruce Wood. The results clearly showed that leaching of boron from spruce Wood Impregnated with preservative solutions based on boric acid and liquefied Wood was significantly reduced.
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Sorption properties of Wood Impregnated with aqueous solution of boric acid and montan wax emulsion
Journal of Applied Polymer Science, 2010Co-Authors: Boštjan Lesar, Aleš Straže, Miha HumarAbstract:Nonbiocidal techniques for Wood protection have become more and more important in the last few years. One of the possible treatments to enhance Wood durability is use of water repellents. In this research, the influence of one of the possible water repellents, the montan wax emulsion, on the moisturizing and the sorption characteristics of Impregnated Wood was investigated. To achieve a better protection against Wood decay fungi, Wood was Impregnated with montan wax emulsion enriched with boric acid. The equilibrium moisture content (MC) was monitored during the adsorption and the desorption processes at five levels of relative air humidity (RH1 = 20%, RH2 = 33%, RH3 = 65%, RH4 = 88%, and RH5 = 98%). Water repellence efficiency was monitored in the chamber with high RH (87%) and during dipping in the water. Impregnated samples were also exposed outdoors in a covered position for 5 months to determine MC changes according to changes in outdoor humidity and temperature. The results showed that the sorption properties of the Impregnated Wood are strongly related to retention of preservative solutions after impregnation and its composition. Montan wax reduced equilibrium MC of the Impregnated Wood up to 25% (relatively), whereas specimens Impregnated with combination of montan wax and boric acid resulted in decreased MC in some cases and in increased MC in some cases. The Guggenheim–Andersen–deBoer model of sorption isotherms was fitted to experimental data to explain the sorption mechanisms. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
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Re-evaluation of fungicidal properties of boric acid
European Journal of Wood and Wood Products, 2009Co-Authors: Boštjan Lesar, Miha HumarAbstract:Minimal inhibitory fungicidal concentrations of one of the most important biocides were determined in nutrient medium and on Impregnated Wood specimens. The results showed, that brown rot fungi are more sensitive to boric acid than white rot ones. To inhibit growth of Wood decay fungi, lower minimal effective retentions have been determined than reported in previous publications.
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Comparison of standard procedures for estimation of biocides leaching from Impregnated Wood
2008Co-Authors: Boštjan Lesar, Polonca Kralj, Daniel Žlindra, Vesna Kancilija, Miha HumarAbstract:Leaching of active ingredients from Impregnated Wood is one of the most frequently applied criteria for assessing the suitability of Impregnated Wood to be used in outdoor applications. For this purposes, several standard and nonstandard procedures are applied. Within the framework of this research, leaching of copper and boron compounds from Wood, Impregnated with four different Wood preservatives, were compared: (a) aqueous solution of copper sulphate, (b) commercial copper-ethanolamine based solution Silvanolin, (c) aqueous solution of boric acid and, (d) combination of boric acid and montanic wax emulsion. Pressure Impregnated specimens were afterwards leached according to the three different standards: SIST EN 84, SIST EN 1250 and OECD recommendation. The highest portion of leached biocides were determined according to the SIST EN 84 procedure, the lowest portion according to OECD recommendation. All three methods applied, however give us the same ranking of Wood preservatives regarding the amount of emitted active ingredients.
M. R. Rahman - One of the best experts on this subject based on the ideXlab platform.
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Mechanical and Thermal Characterization of Urea-Formaldehyde Impregnated Wood Polymer Nanocomposites (WPNCs)
Wood Polymer Nanocomposites, 2017Co-Authors: M. R. RahmanAbstract:In this study, urea-formaldehyde resin Wood polymer nanocomposites (WPNCs) were investigated. All the WPNCs undergo characterizations. The FT-IR spectra confirmed the impregnation of organic urea-formaldehyde into the raw Wood. Besides, WPNCs were generally more thermally stable over temperature compared to the raw Wood due to the introduction of urea-formaldehyde into the raw Wood. From mechanical testing, WPNCs showed higher MOE and MOR for Eugenia spp. and Xylopia spp., respectively. Besides, WPNCs on Eugenia spp. showed higher Young’s modulus compared to raw Wood and other WPNCs. From the X-ray diffraction patterns, the crystallinity of WPNCs increased with the introduction of urea-formaldehyde resin into raw Wood. The SEM micrograph of WPNCs clearly proved that the void space was fully filled with urea-formaldehyde resins and most of the waxy substance was removed. Therefore, urea-formaldehyde-Impregnated WPNCs showed significantly effective on Eugenia spp., continued by Xylopia spp. and Artocarpus elasticus Wood species.
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Physico-Mechanical, Thermal, and Morphological Properties of Styrene-co-3-(Trimethoxysilyl)Propyl Methacrylate with Clay Impregnated Wood Polymer Nanocomposites
Wood Polymer Nanocomposites, 2017Co-Authors: M. R. Rahman, S. Hamdan, Josephine Chang Hui LaiAbstract:In this study, the physico-mechanical, thermal, and morphological properties of styrene-co-3-(trimethoxysilyl)propyl methacrylate (ST-co-SPMA) with clay Impregnated Wood polymer nanocomposites (WPNCs) were investigated. The WPNCs were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), 3-point bending and free-vibration testing, and Thermogravimetric Analysis (TGA). The FT-IR results showed that the absorbance intensity at 698 cm−1 was higher for ST-co-MSPM-clay-WPNC and ST-
Josephine Chang Hui Lai - One of the best experts on this subject based on the ideXlab platform.
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Physico-Mechanical, Thermal, and Morphological Properties of Styrene-co-3-(Trimethoxysilyl)Propyl Methacrylate with Clay Impregnated Wood Polymer Nanocomposites
Wood Polymer Nanocomposites, 2017Co-Authors: M. R. Rahman, S. Hamdan, Josephine Chang Hui LaiAbstract:In this study, the physico-mechanical, thermal, and morphological properties of styrene-co-3-(trimethoxysilyl)propyl methacrylate (ST-co-SPMA) with clay Impregnated Wood polymer nanocomposites (WPNCs) were investigated. The WPNCs were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), 3-point bending and free-vibration testing, and Thermogravimetric Analysis (TGA). The FT-IR results showed that the absorbance intensity at 698 cm−1 was higher for ST-co-MSPM-clay-WPNC and ST-
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Physico-mechanical, Morphological, and Thermal Properties of Clay Dispersed Styrene-co-Maleic Acid Impregnated Wood Polymer Nanocomposites
Wood Polymer Nanocomposites, 2017Co-Authors: Rezaur Rahman, S. Hamdan, Josephine Chang Hui LaiAbstract:In this study, we evaluate the physical, mechanical, and morphological properties of a clay dispersed styrene-co-glycidyl methacrylate (ST-co-GMA) Impregnated Wood polymer nanocomposite (WPNC). The WPNC was characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), 3-point bending, and free-vibration testing. The FT-IR results showed that the absorbance at 1730 cm−1 was increased for ST-co-GMA-clay-WPNC compared with other nanocomposites and the raw material. The SEM results showed that ST-co-GMA-clay-WPNC had a smoother surface than other nanocomposites and raw Wood. The modulus of elasticity (MOE), modulus of rupture (MOR), and dynamic Young’s moduli (Ed) of WPNCs were considerably increased compared to Wood polymer nanocomposites (WPNCs) and raw Wood. The raw Wood exhibited a higher water uptake (WU) than WPNCs.
